UK light heavyweight Buatsi secured a victory yet disappointing beginning to life under recent management with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a close 10-round fight at the Manchester venue.
But the challenger had his moments, connecting with powerful single shots in a match where the techniques never quite clicked, with excessive holding marring the contest.
The officials had it 96-94 for to Buatsi, with the remaining official a even score.
"It wasn't my greatest display but what defines champions? They win," the victor commented in the arena as he was greeted with boos from the spectators.
The British fighter got back to winning after his first professional defeat - an thrilling contest with Callum Smith in February - to earn a twentieth professional win.
Various analysts believed the challenger, 31, merited the decision but the Derbyshire fighter endured the second setback of his 28-bout career.
Buatsi Earns Victory in Uneventful Match
His career development has slowed in the past few years through promotional disputes and considerable time of inactivity.
Previously predicted as the future of the British fight scene, he now is positioned trying to fulfil that early promise - maybe in what appears to be a ultimate opportunity - under fresh management.
He started carefully, with both competitors prepared to overcommit in a cagey opening few rounds.
The challenger, whose sole prior loss came at super middleweight against his former opponent in 2022 after damaging his hand during the bout, was participating in his second appearance at the higher weight class.
By the halfway stage, Parker had kept it close, making life awkward for Buatsi, who worked behind a protective stance to edge the more effective rounds.
The spectators' acceptance diminished amid constant clinching, with the challenger going down various instances during clinches.
The underdog closed well, but several stanzas were challenging to assess. However, previous titleholder Carl Frampton - working with the broadcast network - had it significantly in favor for Parker, awarding Buatsi just a single round.
The victor moves on, but with the presence of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the journey to titles - judging by this showing - still appears challenging.
Ricky Hatton Tribute Motivates Local Rivalry Battle
In the co-main event, Lyndon Arthur defeated Bradley Rea by split-decision in a excellent Manchester vs Manchester fight to secure the European light-heavyweight belt.
The arena became quiet for a profoundly moving tribute before the fight as 10 bells rang in remembrance of Manchester's own Ricky Hatton, who succumbed aged 46 in recently.
It was the initial significant broadcast match card in the location since Hatton's passing. As the last bell faded, the stillness transitioned to a roar of "only one Hatton".
The action during the bout reflected the feeling. Arthur was knocked down by a left hook squarely on the face in the initial stage, getting up unsteadily to his position on the referee's count.
But the Manchester United-red attire of the fighter soon came forward again. Across the ring, Rea - in competitive blue - was marked up soon, significant bruising forming under his face as the pair landed hard punches.
The challenger, 27, delivered effective strikes but the champion, 34, responded in kind with powerful upward punches as the action seldom decreased over the full distance.
Arthur edged the result with scoring tallies of 114-114, close margin and 115-112, but both fighters were relentless and full of heart, everything their hero Hatton represented.
